"感谢您的关心"怎么翻译比较正式啊？（书信中）谢谢

Thanks for your concern.

Thank you for your concern.

appreciate v. 欣赏,感激,赏识

I appreciate your concern.
I really appreciate your concern.

Thanks for your caring all long.
感谢您一直以来的关照。

综合一下，“感谢”可以用thanks、thank you、appreciate，
“关心”可以用concern、caring.

然后去自由搭配吧，呵呵。

书信中，比较正式的
- appreciate your concern

thank you for your graciousness {正式}
thank you for your concern{随意}

应该用thanks for your concerning. concern是关心的意思。

Thanks for your concern.